Vehicle Friction Control Device Mode Switching
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Solution Overview
Problem
Repeated switching of friction control devices between different friction modes in vehicle suspension systems results in less than optimal vehicle performance.
Innovation Solution
A vehicle control system that includes a controller capable of detecting vehicular speed and changing the operation of friction control devices, such as suspension dampers and ball joints, between different friction modes based on threshold speed values, preventing repeated switching by implementing a friction mode schedule and potentially using a time delay or reduced speed signal resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If friction control devices are selectively varied between nominal friction mode and increased friction mode to affect vehicle performance, then vehicle handling and performance are improved, but repeated switching between different friction modes results in less than optimal vehicle performance
Solution Approach 1:
The control system implements a time delay mechanism that prevents immediate switching back to a previous friction mode after a mode change. This preliminary action waits for a predetermined time period to elapse before allowing another mode change, thereby preventing rapid repeated switching and stabilizing vehicle performance while maintaining friction mode adaptability when needed
Solution Approach 2:
The system establishes a periodic control pattern where friction mode changes are spaced by a predetermined time interval. This periodic action creates a rhythm in mode switching that prevents continuous rapid changes, ensuring stable vehicle performance while still allowing periodic adaptation to changing driving conditions
2Adaptability or versatility
If friction control devices switch between different friction modes based on speed thresholds, then vehicle performance is optimized for different speed conditions, but repeated switching occurs when vehicle speed fluctuates near threshold values
Solution Approach 1:
The control system waits for a predetermined time period to elapse before allowing another friction mode change after a switching event. This preliminary waiting period prevents immediate back-and-forth switching when vehicle speed fluctuates near threshold values, reducing control complexity while maintaining speed-based adaptation
Solution Approach 2:
The time delay mechanism acts as a cushion against rapid mode changes by absorbing the effect of speed fluctuations near thresholds. This beforehand cushioning prevents the control system from reacting to temporary speed variations, reducing unnecessary mode switches and control complexity
Data Source
AI summary
Systems and methods for controlling a vehicle including a friction control device are provided. A method of controlling the vehicle includes operating at least one friction control device in a first of a plurality of friction modes, detecting a vehicular speed, changing operation of the at least one friction control device from the first friction mode to a second of the plurality of friction modes in response to the vehicular speed exceeding a first threshold speed value, and changing operation of the at least one friction control device from the second friction mode to the first friction mode in response to the vehicular speed falling below a second threshold speed value that is less than the first threshold speed value. The second friction mode is associated with a higher level of resistance than the first friction mode.